Glass sheet shaping frame

ABSTRACT

A shaping frame for engaging the peripheral portion of a glass sheet during shaping and tempering comprising a rigid reinforcing member aligned in offset relation to the margin of the glass sheet treated and screen means to space said glass sheet from said rigid reinforcing member, said screen means preferably comprising a heavy wire mesh supported on the rigid reinforcing member and a fine wire mesh that contacts the glass supported in spaced relation to said rigid reinforcing member by the heavy wire mesh.

o United States Patent 11 1 1111 3,741,743 Seymour I June 26, 1973' [541GLASS SHEET SHAPING FRAME 2,729,032 1/1956 White 65/289 3,298,809 1/1967Barch et al. 65/287 (761 Samuel Seymmlr, 26 Crystal 3,586,492 6/1971McMaster 65/287 Dnve, Oakmont, 15139 3,310,273 3/1967 Seymour 65/287 x[22] Filed: July 31, 1972 Primary Examiner-Arthur D. Kellogg [21] PP276,877 Attorney-Russel A. Eberly v Related US. Application Data [63]Continuation-in-part of set. N0. 83,935, Oct. 26, [57] ABSTRACT 1970,abandoned. A shaping frame for engaging the per1pheral portion of I aglass sheet during shaping and tempering comprising [52] us. Cl 65/287,65/288, 65/374 a rig d inf cing member aligned in offset relation to['51] Int. Cl C03b 23/02 the margin of the glass sheet treated andscreen means [58] Field of Search 65/287, 288, 289, to sp aid glass sh tfrom said rigid reinforcing 65/290, 291, 104, 374 member, said screenmeans preferably comprising a heavy wire mesh supported on the rigidreinforcing [561' Y 7 References Cited member and a fine wire mesh thatcontacts the glass UNITED STATES A EN supported in spaced relation tosaid rigid reinforcing 2,297,315 9/1942 Owen .L 65/287' member by theheavy mesh" 2,720,729 10/1955 Rugg 12 Claims, 6 Drawing Figures PateniedJune 26, 1973 2 Sheets-Sheet 1 Patented June 26, 1973 2 Sheets-Sheet 2WM vm GLASS SHEET SHAPING FRAME CROSS-REFERENCE TO RELATED APPLICATIONSThis application is a continuation-in-part of U.S. Pat. application Ser.No. 83,935 of Samuel L. Seymour, filed Oct. 26, 1970, for BENDING GLASSSHEETS, now abandoned.

BACKGROUND OF THE INVENTION The present invention relates to bending andtempering glass sheets. When glass sheets are bent and tempered, theyare heated to a temperature above the deformation temperature of theglass, usually on the order of l,200 Fahrenheit to 1,250 Fahrenheit, andthen rapidly quenched after they either sag by gravity or are pressedbetween complementary shaping molds to a desired shape.

Usually, glass sheets are engaged by the edge surface of one or moreshaping frames comprising shaping rails that conform to the outline andcontour desired slightly inward of the periphery of the glass sheet. Theglass conforms to the shape of the shaping rails while heat softened andthen, immediately after shaping, the rapid quenching cools the glasssheet periphery relatively rapidly while the rate of cooling of the linein contact with the outline shaping rails isretarded. Thus, when theentire glass sheet ultimately cools to below the strain point of theglass, the periphery is stressed in compression while the line of glasswhose cooling rate was thus retarded is stressed in tension. While it isknown to serrate the shaped edge surface of a shaping rail and/or toperforate the shaping rail to reduce the thermal effect of the mold railon the glass sheet, the prior art has still failed to avoid producing amaximum residual tension stress in the portion of the bent glass sheetthat engages a rail during the quenching step that causes the. bentglass sheet to fracture sufficiently frequently during te'mpering to bea production problem. When glass is tempered, it develops a skin thatincludes its marginal edge stressed in compression surrounding aninterior stressed in tension. Since glass is notoriously strong incompression and weak in tension, it is important to limit the locationof the tension stress developed to the interior of the tempered glass toavoid the possibility of spontaneous breakage.

DESCRIPTION OF THE PRIOR ART of the glass during the rapid quenching.

U.S. Pat. No. 2,408,526 to Minton shows a gravity sag mold with a strandof non-combustible material, such as asbestos, which spaces the glassfrom direct contact with the mold. This spacing reduces the effect ofthe mold mass on the rate of temperature change in the glass portionengaging the mold rail during the thermal processing incidental totempering. Unfortunately, this spacing material is worn by abrasion andmust be replaced frequently.

U.S. Pat. No. 2,897,632 to Fowler et al. confirms the need for stressingglass sheet edges in compression and teaches that glass sheets bent andcooled on outline molds develop tension stress not only in portionsengaging the mold but in other portions not engaging but sufficientlyclose to heavy metal to be in heatexchanging relation thereto during abending and cooling operation. The area between two spaced lines oftension stress develops a compression stress sufficient for the edge ofa glass sheet. This patent suggests cutting the bent glass along theline of compression stress established between two spaced lines oftension stress to form a strong edge.

U.S. Pat. No. 3,256,080 to Vranken press bends hot glasssheets byengaging the opposite major surfaces inward of the margins with shapingframes that continue to engage the shaped glass during quenching. Theperiphery of the glass cools relatively rapidly to impart a compressiveedge stress, but the glass portionengaged by the frames develops tensionstresses of a magnitude sufficient to cause spontaneous breakage.

U.S. Pat. No. 3,310,273 to Seymour shows apparatus supporting the bottomedge of glass sheets with a wire mesh supported on a rigid member. Thewire mesh does not impose a'banding force on a major surface of theglass sheet.

U.S. Pat. No. 3,5 86,492 to McMaster shows a discontinuous shaping frameconforming to the outline of a glass sheet to be bent and comprising aseries of pointed teeth spaced about the periphery of the frame. Eachtooth has its upper edge forming a linear sheet contacting area thatextends normal to the tangent of the outline of the shaping frame. Astainless steel wire mesh screen is held in position on the frame andextends downward in thespace between teeth so that only the portions ofthe wires of the mesh screen over the teeth contact the glass sheet.Since the teeth extend from inside to outside the marginal edge of asupported glass sheet, the mass of each tooth tends to develop a line oftension stress extending inward from the edge of glass sheets supportedon the frame during shaping and tempering. The glass sheets producedonthe shaping frame of this patent develop a series of spaced lines havingeither less compression stress than the remainder of the glass edge oreven tension stress. Any of these lines is a potential source of glassbreakage.

SUMMARY OF THE INVENTION The present invention provides a novel meansfor spacing one or both major surface of a glass sheet from directcontact with the shaping surface of arelatively heavy shaping rail orshaping frame that also engages the bent glass sheet during itsquenching in prior art structures. The novel spacing means is screenmeans made of a material that is not easily worn by abrasion at elevatedtemperatures, such as stainless steel, and a preferred embodiment ofsaid screen means comprises a relatively heavy wire mesh supported onthe-mold rail and a relatively fine wire mesh supported on therelatively'heavy mesh, the latter serving to space the major surface ofthe glass sheet from the shaping rail. In case the apparatus is of theypress bending type with two complementary shaping frames, both molds areso modified. In case the apparatus is of the press bending typecomprising a solid shaping member and a shaping frame, only the shapingframe is so modified.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be betterunderstood in the light of a description of certain preferredembodiments thereof. In the drawings that form part of the descriptionand where like reference numbers refer to like structural elements,

FIG. 1 is a perspective view of a jointed mold that may either be one ofa pair of press bending molds or may be a gravity sagging mold that ismodified according to the present invention;

FIG. 2 is a cross-sectional view taken along the lines IIll of FIG. 1;

FIG. 3 is a fragmentary enlarged perspective view of a portion of theapparatus shown in FIG. 1;

FIG. 4 is a view similar to FIG. 2 of an alternate embodiment;

FIG. 5 is a similar view of still another embodiment, and

FIG. 6 is a fragmentary showing of press bending apparatus using thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1 to 3 show a frame moldof the jointed or hinged type, although the mold may be a solidring-type frame and may be either one of a pair of complementary pressbending molds adapted to engage the opposite major surfaces of a glasssheet during shaping and cooling or a gravity sag type mold that engagesthe marginal portion of a glass sheet to control the configuration towhich the glass sheet sags by gravity and that continues to support themarginal portion of the glass sheet during the cooling that follows heatsagging.

The mold in FIG. 1 comprises a main mold section 10 rigidly connected toa support member 11 and a pivotable mold section 12 pivotally connectedto the main mold section through pivots 14. The support member alsosupports actuating means in the form of a piston 16 whose cylinder isfixed to support member 11 and whose piston rod 18 has a free endincluding a bracket provided with a pin 19 that is slidably connected toa slotted bracket 20 firmly secured to pivotable mold section 12. Thus,piston 16 actuates pivotal movement of the pivotable mold section 12between an open position and a closed mold position about pivots 14 in amanner well known in the art.

FIGS. 2 and 3 show the novel construction of one embodiment of thepresent invention in detail. Each section of the mold comprises a firstshaping rail 22 of 304 stainless steel one-eighth inch thick, 2 incheswide extending lengthwise in parallel relation to the peripheral edge ofa glass sheet G and conforming in outline and contour to the shapedesired for said glass sheet between one-eighth inch and one-half inchinside the peripheral edge surface 24 of the sheet, except forserrations or notches 26 disposed in spaced relation along the upperedge surface 28 of the first shaping rail 22 and recesses 27 (FIG. 1)for receiving fingers of a glass unloader.

An aligned shaping rail 32 is disposed outwardly of the first shapingrail 22, being separated by spacing members 34 welded to the facingsurfaces of shaping rail 22 and 32 at spacings of several inches. Thespacing members 34 and the aligned shaping rail 32 are composed of 304stainless steel. The spacing members 34 are cylinders about 1 A incheshigh and about onefourth inch in diameter and are connected between theshaping rail 22 and the aligned shaping rail 32 in such a manner thatthe spacing members are recessed below the upper surface 28 includingthe recesses 26 of the shaping rail 22.

Aligned shaping rail 32 has recesses 27 and notches 36 aligned withelements 27 and 26 of rail 22. In addition, the aligned shaping rail 32has an upper edge surface 38 parallel to the upper edge surface 28 ofthe shaping rail 22. Thus, the edge surfaces 28 and 38 are aligned, theedge surface 28 conforming in contour and outline to the shape desiredfor the glass sheet G at least one-eighth inch inside of the glassperipheral edge surface 24 while edge surface 38 conforms to saiddesired shape along a contour disposed at least one-eighth inch outsideof the peripheral glass edge surface 24. According to the presentinvention, screen means bridging the space between the shaping rail 22and the aligned outer shaping rail 32 supports the margin of the glasssheet with the peripheral glass edge'surface 24 spaced from the alignedrail 32 sufficient distance to let tempering air escape between thesurface 24 and outer rail 32.

In the preferred embodiment of the present invention, the screen meansconsists essentially of two layers of inverted channel-shaped meshcomprising a relatively heavy wire mesh 40 having a web 42 and arelatively fine wire mesh 44 having a web 46. The first, relativelyheavy wire mesh 40 is composed of 304 stainless steel 12 X 12 meshcomposed of wire of 0.023 inch diameter containing 52 percent open area.Its web 42 is supported on the upper edge surfaces 28 and 38 and bridgesthe gap therebetween with the walls of the relatively heavy metal wiremesh 40 extending along the outer walls of the shaping rail 22 andaligned shaping rail 32.

The relatively fine wire mesh 44 is composed of 62 X 62 mesh wire of0.004 inch diameter of 304 stainless steel containing 51 percent openarea in spaced relation to the upper edge surfaces 28 and 38 with web 46carried on web 42. Wires 48 extend through openings in one downwardlyextending wall of fine wire mesh 44 and around the bottom of the shapingrail 22 and aligned shaping rail 32 through openings in the oppositedownwardly extending wall of the inverted channel-shaped member ofrelatively fine wire mesh 44 to secure the two layers of wire mesh 40and 44 of the shaping rails 22 and 32.

From the above, it is obvious that the relatively fine wire mesh engagesthe marginal portion of the major surface of the glass sheet and therelatively heavy mesh reinforces said relatively fine wire mesh.

The open area of the mesh permits tempering medium to cool the edge 'ofthe glass sheet at a much more rapid rate than the portion of the glasssheet facing the shaping rail 22. Hence, each layer of wire mesh musthave a minimum of 40 percent open area.

The heavy mesh 40 must be sufficiently rigid to bridge the space betweenshaping rail 22 and aligned outer rail 32 and support the fine mesh 44without sagging. Hence, the wire for the heavy mesh 40 must be at least10 mils in diameter. However, the wire for the heavy mesh 40 must not beso thick that it would retard the cooling rate of the adjacent glassportion to such an extent that it would cause the adjacent glass todevelop a temperature gradient so steep across the glass surface as todevelop a tension stress large enough to cause surface cracks or ventsin the glass. Therefore, the heavy wire mesh must be composed of wirehaving a maximum diameter of approximately 30 mils.

The fine mesh 44 preferably also has a minimum of 40 percent open areaand is preferably approximately 1.5 mils to 6 mils in diameter with acorresponding mesh of 200 by 200 to 40 by 40. 1

As an alternative embodiment, a single layer of wire mesh 45 may besubstituted for the double layer. in such a case, the wire mesh musthave a minimum of 40 percent open area and be composed of wire rangingin diameter from approximately 0.003 inch for 105 by 105 mesh toapproximately 0.006 inch for 40 by 40 mesh. FIG. 5 shows thisembodiment.

The following tables list suitable mesh for single and double layers andacceptable ranges of wire diameters suitable for the heavy mesh and finemesh of the two layer embodiment and a range of acceptable wirediameters for a single layer embodiment.

TABLE I Suitable Wire Mesh Screens for Glass Bending Molds Type of'layerI Mesh Wire Diameter Open Area Double Layer Embodiment Heavy Mesh 12 X12 .023 inch 52% Heavy Mesh 30 X 30 .012 inch 41% Fine Mesh 40 X 40 .006inch 52% Fine Mesh 60 X 60 .0055 inch 45% Fine Mesh 180 X 180 .0018 inch46% Fine Mesh 200 X 200 .0015 inch 49% Single Layer EmbodimentSin'gIeMesh 40 X 40 .006 inch 52% Single Mesh 60 X 60 .0055. inch 45%Single Mesh 84 X 84 .004 inch 45% Single Mesh 105 X I05 .003 inch 47TABLE 11 RANGE OF' ACCEPTABLE WIRE MESH A DIAMETER .Ran e for DoubleAcceptable Diameter Minimum Mes Range Open Area Heavy Mun .0l to .030inch wmmmurn Fine Mesh .0015 to .006 inch 40% Minimum Range For Single.003 to .006 inch 40% Minimum Mes In case the present invention is usedin press bending apparatus, the frame-type mold is duplicated with asimilar mold comprising a second shaping rail having an edge shapingsurface complementary to the edge shaping surface 28 of the firstshaping rail 22, a second .aligned shaping rail having an edge shapingsurface complementary to that of the edge shaping surface 38 of thefirst aligned shaping rail 32 and inverted channel-shaped members ofrelatively heavy wire meshlike mesh 40 and of relatively fine wire meshidentical to wire mesh 44 attached to the second shaping rail and theglass from breakage. At the same time, the portion of the glass-sheetthat has its cooling rate retarded because of its direct contact withthe relatively heavy shaping rail. if the prior art teaching asevidenced by the in direct engagement with the shaping frame is now inspaced relation to the shaping frame during cooling, thus causing lessretardation of the cooling rate and a lower maximum tension stressresults. Therefore, glass sheets bent and tempered while engaged bymolds modified according to the present invention have lower tensionstresses, thus resulting in fewer production losses due to tensionstress breakage.

FIG. shows an alternate embodiment of the present invention in which theshaping mold comprises a frame including a continuous or jointed type ofsingle shaping rail 52, instead of the pair of spaced shaping rails 22and 32, provided with notches 26 and having the previously describedso-called double layer embodiment comprising an inverted channel memberof relatively heavy wire mesh 40 having an open area of at least 40 percent and composed of wire having a diameter of approximately 0.01 inchto approximately 0.03 inch directly over the shaping rail 52 withanother inverted channel member of relatively fine wire mesh 44 havingan open area of at least 40 percent and composed of wire having adiameter of approximately 0.0015 inch to approximately 0.006 inchsuperimposed over mesh 40 and attachment wires 48 securing the invertedchannel members to the shaping rail 52 as in the prior embodiment. Aswith the other embodiment, a complementary shaping rail may be used incooperation with the shaping rail 52 for press bending instead ofgravity sagging.

While the invention has been described in the light of improving theconstruction of ring-type molds used for gravity sag bending or forpress bending apparatus comprising a ring-type or frame-type mold incombination with a complementary ring-type mold, it is also contemplatedwithin the scope of the present invention vtouse either embodiment ofthe present invention in cooperation with a continuous male pressbending mold as in U.S. Pat. No. 3,367,763 to Pickavance et al. or witha vacuum-type press bending mold as in U.S. Pat. No. 3,574,588 toNitschke.

FIG. 6 shows an important part of a press bending and temperingapparatus 60 of the type generally shown in said Nitschke patent thatincludes a furnace 61, a bending station 62, and also including atempering station 78 comprising conventional spaced opposed plenumchambers 81 and 82and a conventional unloading station (notshown). Theapparatus 60 includes an elongated apertured gas support bed 64 forsupporting sheets of glass on'a film of gas thereover. The gas supportbed 64 has a first end 66 extending from a first end of the furnace toprovide a loading station.

A conveying means generally indicated at 67 moves a sheet of glass alongthe bed 64 from the first end 66 to a second end 68 disposed in thelower part of the bending station 62. The second end 66 is provided withan endless recessed portion 73 adapted to receive a frame mold 71constructed in the manner described and shown for the variousembodiments of the present invention.

The bending station 62 is disposed above the second end68 of the supportbed 64 and includes an apertured glass sheet supporting surface forsupporting a sheet on The frame mold, which is generally indicated at71,

comprises a pair of outline rails 22 and 32 supporting either a singlelayer of mesh 45 as in FIG. or a double layer of mesh 40 and 44 asdepicted in FIGS. 2 and 3 or a single outline rail 52 with a serratedupper surface supporting mesh layers 40 and 44 as in FIG. 4 to enable awire mesh web 46 serve as the glass sheet supporting surface of the mold71. The latter is supported in centilever fashion from a transfercarriage 75 which moves the frame mold laterally or generallyhorizontally into the tempering station 78 where air is blasted againstthe opposite surfaces of the supported glass; The frame mold 71 isattached to an elevator means 72 supported on carriage 75. The elevator72 is arranged to support the mold 71 in an upper position except whenmold 71 is disposed over the recess 73, when the elevator is free tomove the frame mold 71 between a lower position wherein the mold 71 isreceived in recess 73 and an upper position wherein the mold 71 pressesa supported hot glass sheet against the downward facing shaping surfaceof mold 69 when the latter is in its downward position.

Beyond the shaping station 62 lies a tempering station 78 where glasssupported on the mold 71 is subjected to air blasts. The'use of screenmeans to space the supported glass sheet from direct contact with themold rails permits the free flow of cold air under pressure against theglass surface, particularly along its marginal edge. Transfer carriage75 is supported for horizontal movement so that mold 71 in its upwardposition moves into and through the tempering station 78 between uppernozzles extending downward from an upper plenum 81 and lower nozzlesextending upward from a lower plenum 82. The transfer carriage 75 may bereciprocated while the mold is between plenums 81 and 82 and air isblasted through said nozzles.

In the generally overall operation of the apparatus 60, hot gases aresupplied through the bed 64 to provide a film or blanket of hot gasesover the surface of bed 64. The furnace 61 also includes an upperheatsupply system for supplying heat to the upper surfaces of the sheetsas they move through the furnace. A sheet of glass is disposed on thebed 64 at the loading station 66. The conveying means 67 moves the sheetof glass along the gas support bed 64 toward the second end 68..

During such movement, the sheet of glass is being heated to atemperature to allow it to be deformed or bent. When the sheet of glassreaches the second end 68 of the bed 64, the sheet of glass is at thebending station 62 above the frame mold 71, which is position in thegroove 73 to await the arrival of a glass sheet from the furnace 60. Theelevator means 72 lifts the frame mold 71 to lift the sheet of glassupwardly to allow the sheet to deform or sag under the force of gravityor to press the sheet against the forming surface mold 69 for bendingthe sheet. In the preferred embodiment, a vacuum is applied to theforming surface mold 69 to pull the sheet into conformance with thesurface thereof. An appropriate means may be utilized to apply a vacuumto passages in the forming surface means 69. After the sheet has beencurved or bent, the vacuum is removed from mold 69 thus depositing thebent glass on frame mold 71, actuating mechanism 76 lifts the mold 69,and transfer carriage moves the frame mold 71 laterally or horizontallyto move the sheet into the tempering station where it is cooled,annealed or tempered by pressurized air blasts.

The cooled bent glass sheet is removed from the frame mold 71 and thecarriage 75 returns the unloaded frame mold 71 to the bending station62, elevator means 72 lowers the frame mold 71 into recess 73 andactuating mechanism 76 lowers the upper mold 69 to await the arrival ofthe next glass sheet from the furnace 61 along bed 64.

In each combination, substituting a ring-type mold provided withrelatively fine wire mesh as the means to engage the glass edgeperipheral portion and with relatively heavy wire mesh to space theglass engaging means from the shaping rail or shaping frame serves toreduce the maximum tension stress produced in the bent, tempered glasssheets treated by the apparatus compared to that produced by thecorresponding prior art apparatus. Hence, the present invention reducedthe likelihood of glass breakage resulting from the bending andtempering operation.

The form of the invention shown and described in this disclosurerepresents an illustrative preferred embodiment and certainmodifications thereof. It is understood that various changes may be madewithout departing from the gist of the invention as defined in theclaimed subject matter which follows.

I claim:

1. Apparatus for bending and tempering a glass sheet comprising a firstshaping rail disposed edgewise and having an edge surface conforming inoutline and contour to the shape desired between one-eighth inch andone-half inch inside the periphery of said glass sheet after bending, afirst, relatively heavy wire mesh having at least 40 per cent open areasupported by said shaping rail, and a first, relatively fine wire meshhaving at least 40 percent open area supported by said first, relativelyheavy mesh and positioned to engage a major surface of said glass sheetin its peripheral portion, said relatively heavy mesh being composed ofwire having a diameter of approximately 0.01 inch to approxi 0.03 inchand said relatively fine mesh being composed of wire having a diameterof approximately 0.0015 inch to approximately 0.006 inch.

2. Apparatus as in claim 1, wherein said wire mesh is composed ofstainless steel.

3. Apparatus in claim 1, further including a second shaping raildisposed edgewise and having an edge surface complementary to said edgesurface of said first shaping rail, a second relatively heavy wire meshsimilar to said first relatively heavy wire mesh supported by saidsecond rail and a second, relatively fine mesh similar to said firstrelatively fine wire mesh supported by said second, relatively heavymesh and positioned to engage the opposite surface of said glass sheetin its peripheral portion, whereby the opposite major surfaces of saidglass sheet are engaged between said first and second, relatively finewire meshes in spaced relation to said shaping rails during said bendingand tempering.

4. Apparatus as in claim 3, wherein said wire mesh is composed ofstainless steel.

5. Apparatus as in claim 1, further comprising a first aligned shapingrail disposed outwardly of said first shaping rail and having an edgesurface aligned with said edge surface of said first shaping rail, meansinterconnecting said first shaping rail and said first aligned shapingrail in sufficiently spaced relation to one another that said firstshaping rail is disposed inward of the periphery of said bent glasssheet and said first aligned shaping rail is disposed outward of theperiphery of said bent sheet, said first, relatively heavy wire mesh insuperimposed position over said edge surfaces to bridge the spacetherebetween, and means for supporting said first, relatively fine wiremesh in superimposed position over said first, relatively heavy wiremesh and said first, relatively heavy wire mesh over said edge surfaces.

6. Apparatus as in claim 5, wherein said wire mesh is composed ofstainless steel.

7. Apparatus as in claim 5, further including a second shaping raildisposed edgewise and having an edge surfacecomplementaryto'said edgesurface of said first shaping rail, and also comprising a second alignedshaping rail disposed outwardly of said second shaping rail and havingan edge surface aligned with said edge surface of said second shapingrail, means interconnecting said second shaping rail and said secondaligned shaping rail in sufficiently spaced relation to one another thatsaidsecond shaping rail is disposed inward of the periphery of said bentglass sheet and said second aligned shaping rail is disposed outward ofthe periphery of said bent sheet, a second, relatively-heavy wire meshsimilar to said first, relatively heavy wire mesh in superimposedrelation over said edge surfaces of said second shaping rail and saidsecond aligned shaping rail to bridge the space therebetween a second,relatively fine wire mesh'similar to said first,,relatively fine wiremesh, and means for supporting said second, relatively fine wire mesh insuperimposed position over said second relatively heavy wire mesh andsaid second,

comprising a first shaping rail disposed edgewise and having an edgesurface conforming in outline and contour to the shape desired betweenone-eighth inch and one-half inch inside the periphery of said glasssheet after bending, a first aligned shaping rail disposed outwardly ofsaid first shaping rail and having an edge surface aligned with andspaced from said edge surface of said first shaping rail and conformingin outline and contour to an outline spaced one-eighth inch to onehalfinch outward of the periphery of said glass sheet after bending, andscreen means having an open area of at least 40 percent and composed ofwire mesh taken from the class of a single layer of wire having adiameter of approximately 0.003 inch to approximately 0.006 inchbridging said space between said edge surfaces and supported by saidshaping rails for supporting the marginal edge portion of said glasssheet between said aligned rails and two layers of wire consistingessentially of a first layer of relatively heavy mesh composed of wirehaving a diameter of approximately 0.01 inch to approximately 0.03 inchin direct contact with said rails and a second layer of relatively lightmesh com posed of wire having a diameter of approximately 0.0015 inch ofapproximately 0.006 inch in direct contact with said relatively heavymesh.

10. Apparatus as in claim 9, wherein said shaping rails form parts of aframe type mold, said mold comprising mold sections pivotallyinterconnected to one another, and means operatively connected to atleast one of said mold sections to move said connected mold sectionbetween an open position and a closed mold position, said first shapingrail and'said first aligned shaping rail being sectionalized to forminterconnected shaping rail sections conforming to different of saidmold sections.

11. Apparatus as in claim 9, wherein said screen means comprises asingle layer of stainless steel wire mesh. a I

12. Apparatus as in claim 9, further including a vacuum type mold havinga contour conforming to those of said first shaping rail and said firstaligned shaping rail and means to provide relative movement between saidshaping rails and said vacuum type mold.

I i I i

1. Apparatus for bending and tempering a glass sheet comprising a first shaping rail disposed edgewise and having an edge surface conforming in outline and contour to the shape desired between one-eighth inch and one-half inch inside the periphery of said glass sheet after bending, a first, relatively heavy wire mesh having at least 40 per cent open area supported by said shaping rail, and a first, relatively fine wire mesh having at least 40 percent open area supported by said first, relatively heavy mesh and positioned to engage a major surface of said glass sheet in its peripheral portion, said relatively heavy mesh being composed of wire having a diameter of approximately 0.01 inch to approxi 0.03 inch and said relatively fine mesh being composed of wire having a diameter of approximately 0.0015 inch to approximately 0.006 inch.
 2. Apparatus as in claim 1, wherein said wire mesh is composed of stainless steel.
 3. Apparatus in claim 1, further including a second shaping rail disposed edgewise and having an edge surface complementary to saId edge surface of said first shaping rail, a second relatively heavy wire mesh similar to said first relatively heavy wire mesh supported by said second rail and a second, relatively fine mesh similar to said first relatively fine wire mesh supported by said second, relatively heavy mesh and positioned to engage the opposite surface of said glass sheet in its peripheral portion, whereby the opposite major surfaces of said glass sheet are engaged between said first and second, relatively fine wire meshes in spaced relation to said shaping rails during said bending and tempering.
 4. Apparatus as in claim 3, wherein said wire mesh is composed of stainless steel.
 5. Apparatus as in claim 1, further comprising a first aligned shaping rail disposed outwardly of said first shaping rail and having an edge surface aligned with said edge surface of said first shaping rail, means interconnecting said first shaping rail and said first aligned shaping rail in sufficiently spaced relation to one another that said first shaping rail is disposed inward of the periphery of said bent glass sheet and said first aligned shaping rail is disposed outward of the periphery of said bent sheet, said first, relatively heavy wire mesh in superimposed position over said edge surfaces to bridge the space therebetween, and means for supporting said first, relatively fine wire mesh in superimposed position over said first, relatively heavy wire mesh and said first, relatively heavy wire mesh over said edge surfaces.
 6. Apparatus as in claim 5, wherein said wire mesh is composed of stainless steel.
 7. Apparatus as in claim 5, further including a second shaping rail disposed edgewise and having an edge surface complementary to said edge surface of said first shaping rail, and also comprising a second aligned shaping rail disposed outwardly of said second shaping rail and having an edge surface aligned with said edge surface of said second shaping rail, means interconnecting said second shaping rail and said second aligned shaping rail in sufficiently spaced relation to one another that said second shaping rail is disposed inward of the periphery of said bent glass sheet and said second aligned shaping rail is disposed outward of the periphery of said bent sheet, a second, relatively heavy wire mesh similar to said first, relatively heavy wire mesh in superimposed relation over said edge surfaces of said second shaping rail and said second aligned shaping rail to bridge the space therebetween a second, relatively fine wire mesh similar to said first, relatively fine wire mesh, and means for supporting said second, relatively fine wire mesh in superimposed position over said second relatively heavy wire mesh and said second, relatively heavy wire mesh over said edge surfaces.
 8. Apparatus as in claim 7, wherein said wire mesh is composed of stainless steel.
 9. Apparatus for bending and tempering a glass sheet comprising a first shaping rail disposed edgewise and having an edge surface conforming in outline and contour to the shape desired between one-eighth inch and one-half inch inside the periphery of said glass sheet after bending, a first aligned shaping rail disposed outwardly of said first shaping rail and having an edge surface aligned with and spaced from said edge surface of said first shaping rail and conforming in outline and contour to an outline spaced one-eighth inch to one-half inch outward of the periphery of said glass sheet after bending, and screen means having an open area of at least 40 percent and composed of wire mesh taken from the class of a single layer of wire having a diameter of approximately 0.003 inch to approximately 0.006 inch bridging said space between said edge surfaces and supported by said shaping rails for supporting the marginal edge portion of said glass sheet between said aligned rails and two layers of wire consisting essentially of a first layer of relatively heavy mesh composed of wire having a diameter of approximately 0.01 inch to approximately 0.03 inch in direct contact with said rails and a second layer of relatively light mesh composed of wire having a diameter of approximately 0.0015 inch of approximately 0.006 inch in direct contact with said relatively heavy mesh.
 10. Apparatus as in claim 9, wherein said shaping rails form parts of a frame type mold, said mold comprising mold sections pivotally interconnected to one another, and means operatively connected to at least one of said mold sections to move said connected mold section between an open position and a closed mold position, said first shaping rail and said first aligned shaping rail being sectionalized to form interconnected shaping rail sections conforming to different of said mold sections.
 11. Apparatus as in claim 9, wherein said screen means comprises a single layer of stainless steel wire mesh.
 12. Apparatus as in claim 9, further including a vacuum type mold having a contour conforming to those of said first shaping rail and said first aligned shaping rail and means to provide relative movement between said shaping rails and said vacuum type mold. 